Arduinos and temperature sensing

I was one of the lucky ones, and got in on the SparkFun "free day"; basically, they gave away $100 off of any order (with no minimum, so you could literally just order $100 of stuff) to anyone lucky enough to be able to submit an order during the ordering period, which was pretty tricky given how badly their servers melted under the load. :-)

Anyway, one of the things I picked up was an Arduino starter kit; an Arduino Duemilanove (the guts of the system), along with a bunch of small sensors, LEDs, and other widgets to help you build stuff with it. Learning a new toy like this always requires that I give myself a real project to tackle with it; if I don't actually "scratch an itch" with it, it ends up getting relegated to "cute toy" status pretty quickly.

As luck would have it, a project presents itself: my wife hates our "programmable" (and I use the term loosely) thermostat, and I'm not prepared to pay a king's ransom for what is basically a small microcontroller and about $15 in parts. So, tonight's project was diving into reading a simple 10K thermistor, and producing some kind of useful output. Turns out, it was much easier than expected. I borrowed a bit of code from both a tri-color LED example, and some example thermistor code, and produced the following sketch that displays green when the temperature is comfortable (by my definition, anyway), red when it's hot, blue when it's cold, and gradiants in-between leading up to the extremes.